High power and excellent beam quality rod Yb: YAG regenerative amplifier

This paper demonstrates a laser diode double-ended pumped Yb: YAG rod regenerative amplifier (RA) with an average power of 37 W, which substantially exceeds the performance of previously reported bulk Yb: YAG medium RAs. Compared to other bulk Yb: YAG medium RAs, we have introduced several enhancements in thermal management, such as employing a double-ended pump to reduce the temperature gradient inside the crystal, and the cooling efficiency is significantly enhanced by designed heat sink. As a result, the thermal effect is effectively suppressed. The system attains high average output power and power stability (RMS = 0.56%) at a pulse repetition rate of 400 kHz. In addition, the output beam maintains excellent quality even under varying high pump powers, demonstrating an \(M^2\) $M^2$ consistently below 1.1.